Retaining mechanisms for prosthetic heart valves

ABSTRACT

According to one representative embodiment, a method of treating aortic insufficiency comprises delivering a support structure to a position around the leaflets of a native heart valve. The support structure comprises an annular body defining an interior and at least one projection extending radially inwardly from the annular body. An expandable prosthetic heart valve can be advanced into the native heart valve and into the interior of the annular body. The prosthetic heart valve can be expanded into contact with the leaflets of the native valve, thereby causing the leaflets of the native valve to be frictionally secured between an inner surface of the annular body and an outer surface of the prosthetic heart valve and causing the at least one projection and a portion of one of the leaflets contacted by the at least one projection to extend into an opening of the frame of the prosthetic valve.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims the benefit of U.S. ProvisionalApplication No. 61/729,109, filed Nov. 21, 2012, which is incorporatedherein by reference.

OTHER RELATED APPLICATIONS

The following applications, which are incorporated herein by reference,disclose retaining mechanisms for prosthetic heart valves and deliverysystems for implanting such retaining mechanisms in the heart: U.S. Pat.No. 8,323,335, issued Dec. 4, 2012, and U.S. application Ser. No.13/188,988, filed Jul. 22, 2011 (published as U.S. Patent ApplicationPublication No. 2012/0022633 A1).

FIELD

This application relates to methods, systems, and apparatus for safelyreplacing native heart valves with prosthetic heart valves.

BACKGROUND

Prosthetic heart valves have been used for many years to treat cardiacvalvular disorders. The native heart valves (such as the aortic,pulmonary, and mitral valves) serve critical functions in assuring theforward flow of an adequate supply of blood through the cardiovascularsystem. These heart valves can be rendered less effective by congenital,inflammatory, or infectious conditions. Such conditions can eventuallylead to serious cardiovascular compromise or death. For many years thedefinitive treatment for such disorders was the surgical repair orreplacement of the valve during open heart surgery, but such surgeriesare dangerous and prone to complication.

More recently a transvascular technique has been developed forintroducing and implanting a prosthetic heart valve using a flexiblecatheter in a manner that is less invasive than open heart surgery. Inthis technique, a prosthetic valve is mounted in a crimped state on theend portion of a flexible catheter and advanced through a blood vesselof the patient until the valve reaches the implantation site. The valveat the catheter tip is then expanded to its functional size at the siteof the defective native valve, such as by inflating a balloon on whichthe valve is mounted. Alternatively, the valve can have a resilient,self-expanding stent or frame that expands the valve to its functionalsize when it is advanced from a delivery sheath at the distal end of thecatheter.

Balloon-expandable valves are commonly used for treating heart valvestenosis, a condition in which the leaflets of a valve (e.g., an aorticvalve) become hardened with calcium. The hardened leaflets provide agood support structure on which the valve can be anchored within thevalve annulus. Further, the catheter balloon can apply sufficientexpanding force to anchor the frame of the prosthetic valve to thesurrounding calcified tissue. There are several heart conditions,however, that do not involve hardened valve leaflets but which are stilldesirably treated by valve replacement. For example, aorticinsufficiency (or aortic regurgitation) occurs when an aortic valve doesnot close properly, allowing blood to flow back into the left ventricle.One cause for aortic insufficiency is a dilated aortic annulus, whichprevents the aortic valve from closing tightly. In such cases, theleaflets are usually too soft to provide sufficient support for aballoon-expandable prosthetic valve. Additionally, the diameter of theaortic annulus may continue to change over time, making it dangerous toinstall a prosthetic valve that is not reliably secured in the valveannulus. Mitral insufficiency (or mitral regurgitation) involves thesesame issues, but affects the mitral valve.

Self-expanding prosthetic valves are sometimes used for replacingdefective native valves with non-calcified leaflets. Self-expandingprosthetic valves, however, suffer from a number of significantdrawbacks. For example, once a self-expanding prosthetic valve is placedwithin the patient's defective heart valve (e.g., the aorta or mitralvalve), it continues to exert an outward force on the valve annulus.This continuous, outward pressure can cause the valve annulus to dilatefurther, exacerbating the condition that the prosthetic valve wasintended to treat. Additionally, when implanting a self-expanding valve,the outward biasing force of the valve's frame tends to cause the valveto be ejected very quickly from the distal end of a delivery sheath,making delivery of the valve very difficult and potentially dangerous tothe patient.

The size of the prosthetic valve to be implanted into a patient can alsobe problematic when treating aortic or mitral insufficiency.Specifically, the size of a prosthetic valve used to treat aortic ormitral insufficiency is typically larger than a prosthetic valve used totreat aortic or mitral stenosis. This larger valve size makes thedelivery procedure much more difficult and dangerous to the patient.

Accordingly, there exists a need for improved methods, systems, andapparatus for delivering expandable prosthetic heart valves (e.g.,balloon-expandable prosthetic valves). Embodiments of the methods,systems, and apparatus desirably can be used to replace native heartvalves that do not have calcified leaflets (e.g., aortic valvessuffering from aortic insufficiency). Furthermore, embodiments of themethods, systems, and apparatus desirably enable precise and controlleddelivery of the prosthetic valves.

SUMMARY

According to one representative embodiment, a method of treating aorticinsufficiency comprises delivering a support structure to a position onor adjacent to the surface of the outflow side of a native heart valveof a patient. The support structure comprises an annular body definingan interior and at least one projection extending radially inwardly fromthe annular body. The method further includes positioning the supportstructure around the leaflets of the native heart valve such that theleaflets of the native heart valve are located within the interior ofthe annular body. An expandable prosthetic heart valve can be advancedinto the native heart valve and into the interior of the annular body.The prosthetic heart valve can comprise a radially expandable annularframe defining a plurality of openings. The prosthetic heart valve canbe expanded into contact with the leaflets of the native valve, therebycausing the leaflets of the native valve to be frictionally securedbetween an inner surface of the annular body and an outer surface of theprosthetic heart valve and causing the at least one projection and aportion of one of the leaflets contacted by the at least one projectionto extend into one of said openings of the frame.

In another representative embodiment, an assembly for treating aorticinsufficiency comprises a prosthetic heart valve and a separate supportstent. The prosthetic heart valve is configured to be implanted within anative heart valve, and comprises a radially expandable annular framedefining a plurality of openings. The support stent is configured to beimplanted around the leaflets of the native heart valve such that thenative leaflets can be frictionally secured between the support stentand the prosthetic valve. The support stent comprises an annular metalframe that defines one or more peaks and one or more valleys along itscircumference. The support stent frame is radially compressible into acompressed state and self-expandable into an uncompressed state andfurther comprises at least one projection comprising a non-metallicmaterial. The at least one projection extends radially inwardly from thesupport stent frame and is configured to press a portion of one of thenative leaflets into one of the openings of the frame of the prostheticvalve.

In another representative embodiment, a delivery apparatus fordelivering a radially self-expandable prosthetic device to a nativeheart valve comprises a first elongated shaft having a distal endportion and a second elongated shaft extending over the first shaft. Aplurality of attachment arms extend distally from the distal end portionof the first shaft, each attachment arm having an aperture configured toreceive an end portion of a retaining arm of the prosthetic device. Aplurality of release wires extend alongside the attachment arms and areconfigured to extend through corresponding openings in the end portionsof the retaining arms when the end portions of the retaining arms areinserted through corresponding openings in the attachment arms so as toreleasably secure the prosthetic device to the attachment arms. Aplurality of sheaths extend distally from the distal end of the firstshaft, each sheath extending co-axially over a respective pair of anattachment arm and a release wire so as to maintain the release wire inclose proximity to the attachment arm.

In another representative embodiment, a delivery apparatus fordelivering a radially self-expandable prosthetic device to a nativeheart valve comprises a first elongated shaft having a proximal endportion and a distal end portion. The distal end portion is configuredto be releasably coupled to the prosthetic device during delivery of theprosthetic device into a patient. The apparatus further includes asecond elongated shaft having a proximal end portion and a distal endportion. The second shaft extends over the first shaft, the distal endportion of the second shaft comprising a sheath configured to at leastpartially receive the prosthetic device in a radially compressed state.The second shaft is configured to be selectively bendable. A handle iscoupled to the proximal end portions of the first and second shafts. Thehandle has an adjustment mechanism configured to adjust the curvature ofthe second shaft. The first shaft is allowed to move in a proximaldirection relative to the second shaft and the handle when the secondshaft foreshortens as a result of the adjustment mechanism beingactuated to increase the curvature of the second shaft.

In another representative embodiment, a delivery apparatus fordelivering a radially self-expandable prosthetic device to a nativeheart valve comprises a first elongated shaft having a proximal endportion and a distal end portion. The distal end portion is configuredto be releasably coupled to the prosthetic device during delivery of theprosthetic device into a patient. The delivery apparatus furthercomprises a second elongated shaft having a proximal end portion and adistal end portion, the second shaft extending over the first shaft. Thedistal end portion of the second shaft comprises a sheath configured toat least partially receive the prosthetic device in a radiallycompressed state. A handle is coupled to the proximal end portions ofthe first and second shafts. The handle comprises a rotatable knoboperatively connected to the first shaft and configured to effect axialmovement of the first shaft relative to the second shaft to deploy theprosthetic device from the sheath of the second shaft. The handlefurther comprising a spring configured to provide resistance againstrotation of the knob. In particular embodiments, the resistance of thespring is greater against rotation of the knob in a first direction thanit is against rotation of the knob in a second direction, opposite thefirst direction.

The foregoing and other objects, features, and advantages of theinvention will become more apparent from the following detaileddescription, which proceeds with reference to the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary embodiment of a supportstructure according to the disclosed technology.

FIG. 2 is a cross-sectional view of a native aortic valve with thesupport structure of FIG. 1 positioned therein.

FIGS. 3 and 4 are perspective views of an exemplary delivery system forthe support structure of FIG. 1. In particular, FIG. 3 shows thedelivery system before the support structure is deployed, and FIG. 4shows the delivery system after the support structure is deployed.

FIG. 5 is an exploded view of the components of the exemplary deliverysystem shown in FIGS. 3 and 4.

FIG. 6 is a zoomed-in perspective view showing the mechanism forreleasably connecting the support structure to the exemplary deliverysystem of FIGS. 3 and 4.

FIGS. 7 and 8 are cross-sectional views of a patient's heartillustrating how the delivery system of FIGS. 3 and 4 can operate todeploy the support structure of FIG. 1 to a desired position on thepatient's aortic valve.

FIGS. 9-13 are cross-sectional views of a patient's heart illustratinghow an exemplary transcatheter heart valve (“THV”) can be deployed tothe patient's aortic valve and frictionally secured to the nativeleaflets using the support structure of FIG. 1.

FIGS. 14-15 are perspective views of a support stent, according toanother embodiment.

FIGS. 16-17 are perspective and side elevation views, respectively, ofthe support stent of FIGS. 14-15 shown with the fabric cover removed forpurposes of illustration.

FIG. 18 is an enlarged view of a portion of the support stent of FIGS.14-15 showing a projection of the support stent.

FIGS. 19-21 illustrated a method for forming a suture ball and securingit to the support stent, thereby forming a projection.

FIG. 22 is a perspective view of the support stent having a plurality ofsuture balls secured to the stent.

FIG. 23 is a perspective view of the support stent of FIGS. 14-15mounted around the frame of a prosthetic valve.

FIG. 24 shows a prosthetic valve implanted with a native aortic valveand the support stent of FIGS. 14-15 implanted around the nativeleaflets of the aortic valve such that the native leaflets are pinchedbetween the prosthetic valve and the support stent.

FIG. 25 is a flattened view of the support stent and the prostheticvalve frame shown in FIG. 23.

FIG. 26 is a flattened view of the support stent of FIG. 25 and anotherexample of a prosthetic valve frame.

FIG. 27 is a perspective view of another embodiment of a support stent.

FIG. 28 shows another embodiment of a support stent and a prostheticvalve implanted within the support stent.

FIG. 29 is an enlarged top plan view of a projection of the supportstent of FIG. 28.

FIGS. 30-48 show different techniques and mechanisms for forming aprojection on a support stent.

FIG. 49 shows the distal end portion of a delivery apparatus that can beused to implant a support stent, according to one embodiment.

FIGS. 50-53 are enlarged views showing the releasable connection betweena retaining arm of a support stent and a pair of an attachment arm and arelease wire of the delivery apparatus of FIG. 49.

FIG. 54 is a cross-sectional view of an aortic valve illustrating anexemplary procedure for deploying a support stent around a prostheticheart valve using a dual system approach.

FIGS. 55A-55E are side views of the distal end portion of a deliveryapparatus illustrating premature deployment of a support stent caused bychanging the curvature of the delivery apparatus.

FIG. 56 is an enlarged view of a drive mechanism inside a handle of adelivery apparatus that can prevent premature deployment of a medicalimplant when the curvature of the delivery apparatus is adjusted.

FIG. 57 is a side view of an exemplary handle of a delivery apparatusfor a medical implant, such as a support stent.

FIG. 58 is an enlarged view of the inside of the handle of FIG. 57.

DETAILED DESCRIPTION

General Considerations

Disclosed below are representative embodiments of a support structure(sometimes referred to as a “support stent,” “support frame,” “supportband,” or “support loop”) that can be used to secure a prosthetic heartvalve within a native heart valve. For illustrative purposes,embodiments of the support structure are described as being used tosecure a transcatheter heart valve (“THV”) in the aortic valve or themitral valve of a heart. It should be understood that the disclosedsupport structure and THV can be configured for use with any other heartvalve as well. Also disclosed herein are exemplary methods and systemsfor deploying the support structure and corresponding THV. Although theexemplary methods and systems are mainly described in connection withreplacing an aortic or mitral valve, it should be understood that thedisclosed methods and systems can be adapted to deliver a supportstructure and THV to any heart valve.

For illustrative purposes, certain embodiments of the support structureare described as being used in connection with embodiments of theballoon-expandable THV described in U.S. Patent Application PublicationNo. 2007/0112422 A1 (U.S. application Ser. No. 11/280,063), which ishereby expressly incorporated herein by reference. It should beunderstood, however, that this particular usage is for illustrativepurposes only and should not be construed as limiting. Instead,embodiments of the disclosed support structure can be used to secure awide variety of THVs delivered through a variety of mechanisms (e.g.,self-expanding heart valves, other balloon-expanding heart valves, andthe like). For instance, any of the embodiments described in U.S. Pat.No. 6,730,118 can be used with embodiments of the disclosed supportstructure. U.S. Pat. No. 6,730,118 is hereby expressly incorporatedherein by reference.

For purposes of this description, certain aspects, advantages, and novelfeatures of the embodiments of this disclosure are described herein. Thedescribed methods, systems, and apparatus should not be construed aslimiting in any way. Instead, the present disclosure is directed towardall novel and nonobvious features and aspects of the various disclosedembodiments, alone and in various combinations and sub-combinations withone another. The disclosed methods, systems, and apparatus are notlimited to any specific aspect, feature, or combination thereof, nor dothe disclosed methods, systems, and apparatus require that any one ormore specific advantages be present or problems be solved.

Although the operations of some of the disclosed methods are describedin a particular, sequential order for convenient presentation, it shouldbe understood that this manner of description encompasses rearrangement,unless a particular ordering is required by specific language set forthbelow. For example, operations described sequentially may in some casesbe rearranged or performed concurrently. Moreover, for the sake ofsimplicity, the attached figures may not show the various ways in whichthe disclosed methods, systems, and apparatus can be used in conjunctionwith other systems, methods, and apparatus.

As used herein, the terms “a”, “an”, and “at least one” encompass one ormore of the specified element. That is, if two of a particular elementare present, one of these elements is also present and thus “an” elementis present. The terms “a plurality of” and “plural” mean two or more ofthe specified element.

As used herein, the term “and/or” used between the last two of a list ofelements means any one or more of the listed elements. For example, thephrase “A, B, and/or C” means “A”, “B”, “C”, “A and B”, “A and C”, “Band C”, or “A, B, and C”.

As used herein, the term “coupled” generally means physically coupled orlinked and does not exclude the presence of intermediate elementsbetween the coupled items absent specific contrary language.

Exemplary Embodiments for Replacing Aortic Valves

FIG. 1 is a perspective view showing an exemplary embodiment of asupport stent or frame 10. Support stent 10 has a generally annular ortoroidal body formed from a suitable shape-memory metal or alloy, suchas spring steel, Co—Cr—Ni alloy (Elgiloy®), or nitinol. Desirably, thematerial from which the support stent 10 is fabricated allows thesupport stent to automatically expand to its functional size and shapewhen deployed but also allows the support stent to be radiallycompressed to a smaller profile for delivery through the patient'svasculature. In other embodiments, however, the stent is notself-expanding. In these embodiments, and as more fully explained below,other mechanisms for expanding the stent can be used (e.g., a ballooncatheter).

In the illustrated embodiment, the projection of the support stent 10onto an x-y plane has a generally annular or toroidal shape. Theillustrated support stent 10 further defines a number of peaks andvalleys (or crests and troughs) along its circumference. For example,the support stent 10 is sinusoidally shaped in the z direction. In otherembodiments, the support stent 10 is shaped differently in the zdirection (e.g., sawtooth-shaped, ringlet-shaped, square-wave shaped, orotherwise shaped to include peaks and valleys).

The illustrated support stent 10 includes three peaks 20, 22, 24 andthree valleys 30, 32, 34. In the illustrated embodiment, the peaks 20,22, 24 are positioned above the valleys 30, 32, 34 in the z-direction.In some embodiments, the peaks have greater radii than the valleys 30,32, 34, or vice versa. For instance, in some embodiments, the projectionof the support stent 10 onto an x-y plane forms a closed shape having avariable radius (e.g., a starfish shape).

The size of the support stent 10 can vary from implementation toimplementation. In particular embodiments, the support stent 10 is sizedsuch that the support stent can be positioned within the aorta of apatient at a location adjacent to the aortic valve, therebycircumscribing the aortic valve. Furthermore, in order to frictionallysecure a prosthetic heart valve in its interior, certain embodiments ofthe support stent 10 have a diameter that is equal to or smaller thanthe diameter of the prosthetic heart valve when fully expanded. Inparticular embodiments, for instance, the support stent can have aninner or outer diameter between about 10 mm and about 50 mm (e.g.,between about 17 mm and about 28 mm) and a height between about 5 mm andabout 35 mm (e.g., between about 8 mm and about 18 mm). Furthermore, thethickness of the annular body of the support stent 10 may vary fromembodiment to embodiment, but in certain embodiments is between about0.3 mm and about 1.2 mm.

FIG. 2 is a perspective view of the exemplary support stent 10positioned on the surface of an outflow side of a native aortic valveand further illustrates the shape of the support stent. In particular,it can be seen from FIG. 2 that the valleys 30, 32, 34 of the supportstent 10 are shaped so that they can be placed adjacent to commissures50, 52, 54 of the native leaflets 60, 62, 64 of the aortic valve.Furthermore, in the illustrated embodiment, the peaks 20, 22, 24 areshaped so that they generally approximate or mirror the size and shapeof the leaflets 60, 62, 64 but are slightly smaller and lower than theheight of the leaflets 60, 62, 64 at their tips when the aortic valve isfully opened. In other embodiments, the peaks 20, 22, 24 are oriented sothat they are adjacent to the commissures 50, 52, 54 of the nativeleaflets 60, 62, 64 and the valleys are opposite the apexes of theleaflets 60, 62, 64. The support stent 10 can be positioned in any otherorientation within the aortic valve as well.

It should be understood that the shape of the support stent or frame 10can vary from implementation to implementation. For example, in someembodiments, the support stent is not sinusoidal or otherwise shaped inthe z-plane. In other embodiments, the support stent is shaped as acylindrical band or sleeve. In general, the support stent or frame canbe any shape that defines an interior through which a THV can beinserted, thereby causing the native leaflets of the aortic valve (orother heart valve) to be pinched or securely held between the supportstent and the THV. Furthermore, the support stent can have a morecomplex structure. For example, although the support stent illustratedin FIGS. 1 and 2 is formed from a single annular member (or strut), thesupport stent can comprise multiple annular elements that interlock orare otherwise connected to one another (e.g., via multiple longitudinalmembers).

Returning to FIG. 1, the illustrated support stent 10 also includeretaining arms 21, 23, 25 that can be used to help position and deploythe support stent 10 into its proper location relative to the nativeaortic valve. The retaining arms 21, 23, 25 can have respectiveapertures 26, 27, 28. An exemplary deployment system and procedure fordeploying the support stent 10 using the retaining arms 21, 23, 25 aredescribed in more detail below. The support stent 10 can also have oneor more barbs located on its surface. Such barbs allow the support stent10 to be more securely affixed to the tissue surrounding the stent orthe leaflets of the aorta.

FIGS. 3 and 4 are side views of the distal end portion of an exemplarydelivery apparatus 100 for delivering the support stent 10 to itslocation adjacent the native aortic valve through a patient'svasculature. In particular, FIG. 3 shows the delivery apparatus when thesupport stent 10 is in a compressed, pre-deployed state, whereas FIG. 4shows the delivery apparatus when the support stent 10 is in adecompressed, deployed state. The delivery apparatus 100 comprises aguide catheter 102 having an elongated shaft 104, whose distal end 105is open in the illustrated embodiment. In other embodiments, the distalend 105 of the guide catheter 102 can be tapered into a conical shapecomprising multiple “flaps” forming a protective nose cone that can beurged apart when the support stent 10 and any interior catheters areadvanced therethrough. Furthermore, for illustrative purposes, the guidecatheter 102 is shown as being partially cut away, thus revealing itsinterior.

A proximal end (not shown) of the guide catheter 102 is connected to ahandle of the delivery apparatus 100. During delivery of a supportstent, the handle can be used by a surgeon to advance and retract thedelivery apparatus through the patient's vasculature. In a particularuse, the delivery apparatus 100 is advanced through the aortic arch of apatient's heart in the retrograde direction after having beenpercutaneously inserted through the femoral artery. The guide cathetercan be configured to be selectively steerable or bendable to facilitateadvancement of the delivery system 100 through the patient'svasculature. An exemplary steerable guide catheter as can be used inembodiments of the disclosed technology is described in detail in U.S.Patent Application Publication No. 2007/0005131 A1 (U.S. patentapplication Ser. No. 11/152,288), which is hereby expressly incorporatedherein by reference.

The delivery apparatus 100 also includes a stent delivery catheter 108positioned in the interior of the guide catheter 102. The stent deliverycatheter 108 has an elongated shaft 110 and an outer fork 140 connectedto a distal end portion of the shaft 110. The shaft 110 of the stentdelivery catheter 108 can be configured to be moveable axially relativeto the shaft 104 of the guide catheter 102. Furthermore, the shaft 110of the stent delivery catheter 108 can be sized so that its exteriorwall is adjacent to or in contact with the inner wall of the shaft 104of the guide catheter 102.

The delivery apparatus 100 can also include an inner catheter 118positioned in the interior of the stent deliver catheter 108. The innercatheter 118 can have an elongated shaft 120 and an inner fork 138secured to the distal end portion of the shaft 120. The shaft 120 of theinner catheter 118 can be configured to be moveable axially relative tothe shaft 104 of the guide catheter 102 and relative to the shaft 110 ofthe stent delivery catheter 108. Furthermore, the shaft 120 of the innercatheter 118 can be sized so that its exterior wall is adjacent to or incontact with the inner wall of the shaft 110 of the stent deliverycatheter 108. A guide wire (not shown) can be inserted into the interiorof the inner catheter 118. The guide wire can be used, for example, tohelp ensure proper advancement of the guide catheter 102 and itsinterior catheters through the vasculature of a patient.

As best shown in FIG. 5, a stent retaining mechanism is formed from theinner fork 138 attached to the distal end portion of the shaft 120 ofthe inner catheter 118 and the outer fork 140 attached to the distal endportion of the shaft 110 of the stent delivery catheter 108. The innerfork 138 includes a plurality of flexible inner prongs 141, 142, 143(three in the illustrated embodiment) at its distal end corresponding tothe retaining arms 21, 23, 25 of the support stent 10, and a headportion 144 at its proximal end. The outer fork 140 includes a pluralityof flexible outer prongs 145, 146, 147 (three in the illustratedembodiment) at its distal end corresponding to the retaining arms 21,23, 25 of the stent 10, and a head portion 148 at its proximal end. Thedistal end portions of the outer prongs 145, 146, 147 are formed withrespective apertures 155, 156, 157 sized to receive the retaining arms21, 23, 25.

FIG. 6 is a zoomed-in view of one of the retaining arms 21, 23, 25 as itinterfaces with corresponding prongs of the outer fork 140 and the innerfork 138. In this example, retaining arm 21 is shown, though it shouldbe understood that the retaining mechanism is similarly formed for theretaining arms 23, 25. The distal end portion of the outer prong 145 isformed with the aperture 155. When assembled, the retaining arm 21 ofthe stent is inserted through the aperture 155 of the prong 145 of theouter fork and the prong 141 of the inner fork is inserted through theaperture 26 of the retaining arm 21 so as to retain the retaining arm 21in the aperture 155.

Retracting the inner prong 141 proximally (in the direction of arrow152) to remove the prong from the aperture 26 allows the retaining arm21 to be removed from the aperture 155, effectively releasing theretaining arm from the retaining mechanism. For instance, the outerprong 145 and the retaining arm 21 can be formed such that when theinner prong 141 is withdrawn from the aperture 26, the outer prong 145flexes radially inward (downward in FIG. 7) and/or the retaining arm 21of the support stent flexes radially outward (upward in FIG. 7), therebycausing the retaining arm 21 to be removed from the aperture 155. Inthis manner, the retaining mechanism formed by the inner fork 138 andthe outer fork 140 create a releasable connection with the support stent10 that is secure enough to retain the support stent to the stentdelivery catheter 108 and to allow the user to adjust the position ofthe support stent after it is deployed. When the support stent 10 ispositioned at the desired location adjacent to the leaflets of theaortic valve, the connection between the support stent and the retainingmechanism can be released by retracting the inner fork 138 relative tothe outer fork 140, as further described below. In other embodiments,the functions of the inner fork and the outer fork can be reversed. Forexample, the prongs of the inner fork can be formed with apertures sizedto receive the corresponding retaining arms of the support stent and theprongs of the outer fork can be inserted through the apertures of theretaining arms when the retaining arms are placed through the aperturesof the prongs of the inner fork.

As best shown in the exploded view in FIG. 5, the head portion 144 ofthe inner fork can be connected to the distal end portion of the shaft120 of the inner catheter 118. In the illustrated embodiment, forexample, the head portion 144 of the inner fork is formed with aplurality of angularly spaced, inwardly biased retaining flanges 154. Anend piece of the shaft 120 can be formed as a cylindrical shaft havingan annular groove 121. On the distal side of the annular groove 121, theshaft 120 can have a collar 122 with an outer diameter that is slightlygreater than the diameter defined by the inner free ends of the flanges154. Thus, the inner fork 138 can be secured to the end piece byinserting head portion 144 of the inner fork onto the end piece of theshaft 120 until the flanges 154 flex inwardly into the annular groove121 adjacent the collar 122, thereby forming a snap-fit connectionbetween the head portion 144 and the shaft 120. The head portion 144 canhave a proximal end that engages an annular shoulder 123 of the shaft120 that is slightly larger in diameter so as to prevent the headportion from sliding longitudinally along the shaft 120 in the proximaldirection.

The head portion 148 of the outer fork can be secured to a distal endportion of the shaft 110 of the stent delivery catheter 108 in a similarmanner. As shown in FIG. 5, the head portion 148 can be formed with aplurality of angularly spaced, inwardly biased retaining flanges 155. Anend piece of the shaft 110 can be formed as a cylindrical shaft havingan annular groove 111. On the distal side of the annular groove 111, theshaft 110 can have a collar 112 with an outer diameter that is slightlygreater than the diameter defined by the free ends of the flanges 155.Thus, the outer fork 140 can be secured to the end piece of the shaft110 by inserting the shaft 110 onto the head portion 148 until theflanges flex inwardly into the groove 111, thereby forming a snap-fitconnection between the head portion 148 and the shaft 110. The headportion 148 can have a proximal end that engages an annular shoulder 123of the shaft 110 that is slightly larger so as to prevent the headportion from sliding longitudinally along the shaft 110 in the proximaldirection.

In FIG. 3, the support stent 10 is shown in a radially compressed statein the interior of the elongated shaft 104 of the guide catheter 102. Inthe radially compressed state, the distance along the z-axis between apeak and an adjacent valley of the support stent is greater than thedistance along the z-axis between the peak and the adjacent valley whenthe support stent is in it uncompressed state. The distal end portion ofthe shaft 104 can also be referred to as a delivery sheath for the stent10. In this undeployed and compressed state, the prongs of the outerfork 140 and the inner fork 138 of the stent delivery catheter 108 andthe inner catheter 118 engage the retaining arms 21, 23, 25 of thesupport stent 10 in the manner described above with respect to FIGS. 5and 6. To deploy the support stent 10 in the illustrated embodiment (toadvance the stent from the delivery system), the stent delivery catheter108 and the inner catheter 118 are advanced toward the distal end 105 ofthe guide catheter 102 using one or more control handles or mechanisms(not shown) located at the proximal end of the guide catheter 102. Thisaction causes the support stent 10 to be advanced outwardly through thedistal end 105 of the guide catheter 102 and expand into its relaxed,uncompressed state (shown, for example, in FIGS. 1 and 2).

FIG. 4 is a perspective view showing the support stent 10 after it hasbeen advanced from the distal end of the guide catheter 102. As seen inFIG. 4, the support stent 10 now assumes its relaxed, uncompressed shapebut remains connected to the outer fork 140 and the inner fork 138 atits retaining arms 21, 23, 25. In this configuration, the support stent10 can be rotated (in the clockwise or counter-clockwise directions) orrepositioned (in the proximal and distal directions and/or to adifferent position in the x-y plane) into a proper orientation adjacentto its intended target area. For example, the support stent 10 can bepositioned against the upper surfaces of leaflets of the aortic valve inthe manner illustrated in FIG. 2 while the support stent 10 remainsconnected to the delivery system 100 via the retaining arms 21, 23, 25.As more fully illustrated below in FIGS. 7-12, a prosthetic valve (e.g.,a THV) can be delivered to the aortic valve through a transapicalapproach (e.g., through the apex of the heart and through the leftventricle) and deployed within the native valve such that the prostheticvalve is secured in place by frictional engagement between the supportstent, the native leaflets, and the prosthetic valve.

In particular embodiments, the support stent 10 is shaped so that theTHV can be positioned in the interior of the support stent along withthe native leaflets of the aortic valve. More specifically, the supportstent 10 can be shaped such that the native leaflets become trapped orpinched between the support stent 10 and the exterior of the THV whenthe THV is installed. For instance, the diameter of the support stent 10can be equal to or smaller than the maximum diameter of the THV whenfully expanded, thus causing the THV to be frictionally fit to theleaflets of the aortic valve and the support stent 10. This friction fitcreates a solid foundation for the THV that is independent of the stateor condition of the leaflets in the aortic valve. For example, THVs aremost commonly used for treating aortic stenosis, a condition in whichthe leaflets of the aortic valve become hardened with calcium. Thehardened leaflets typically provide a good support structure foranchoring the THV within the aortic annulus. Other conditions may exist,however, in which it is desirable to implant a THV into the aortic valveand which do not result in a hardening of the leaflets of the aorticvalve. For instance, the support stent 10 can be used as a foundationfor a THV when treating patients with aortic insufficiency. Aorticinsufficiency results when the aortic annulus dilates such that theaortic valve does not close tightly. With this condition, the aorticannulus is larger than normal and would otherwise require a large THV.Using a support stent or frame (such as the support stent or frame 10),however, a smaller THV can be used, thereby making the THV deliveryprocess easier and safer. Furthermore, the use of a support stentprotects against displacement of the THV if there is any furtherdilation of the aortic valve.

A support stent can be used to secure a THV in any situation in whichthe aorta or aortic valve may not be in condition to help support theTHV and is not limited to cases of aortic insufficiency. For example, asupport stent 10 can be used in cases in which the aortic annulus is toodilated or in which the leaflets of the aorta are too weak or soft. Thesupport stent can be used to create an anchor for the THV, for instance,in cases in which the native leaflet tissue is too soft because ofexcess collagen in the aorta.

FIGS. 7-13 illustrate one exemplary procedure for deploying the supportstent and securing a THV to the support stent. In particular, FIGS. 7-8are cross-sectional views through the left side of a patient's heartshowing the acts performed in delivering the support stent 10 throughthe aortic arch to the aortic valve. FIGS. 9-13 are cross-sectionalviews through the left side of a patient's heart showing the actsperformed in deploying a THV 250 and having it engage the support stent10. In order to better illustrate the components of the delivery system100, the guide catheter 102 is shown partially cut away in FIGS. 7-13.For the sake of brevity, certain details concerning the delivery systemof the THV 250 are omitted. Additional details and alternativeembodiments of the delivery system for the THV 250 that may be used withthe support stent described herein are discussed in U.S. PatentApplication Publication No. 2007/0112422 A1 (U.S. patent applicationSer. No. 11/280,063), which is hereby expressly incorporated herein byreference.

FIG. 7 shows the guide catheter 102 of the delivery system 100 as it isadvanced through the aortic arch 202 into a position near the surface ofthe outflow side of the aortic valve 210. The delivery system 100 can beinserted through the femoral artery of the patient and advanced into theaorta in the retrograde direction. FIG. 7 also shows the stent deliverycatheter 108, the inner catheter 118, and the support stent 10. In FIG.7, the support stent 10 is in its radially compressed, pre-deploymentstate. Also seen in FIG. 7 are the outer fork 140 and the inner fork138, which couple the radially compressed support stent 10 to the distalends of the stent delivery catheter 108 and the inner catheter 118,respectively.

FIG. 8 shows the support stent 10 after it has been advanced through thedistal end of the guide catheter 102 and assumes its final, uncompressedshape in a position above and adjacent to the aortic valve 210. Thesupport stent 10 can also be placed directly on the surface of theoutflow side of the aortic valve. FIG. 8 shows that the stent deliverycatheter 108 and the inner catheter 118 have been advanced though thedistal end of the guide catheter 102, thereby pushing the support stent10 out of the guide catheter and allowing it to expand into its naturalshape. In particular embodiments, the support stent 10 is rotated andpositioned as necessary so that the support stent generallycircumscribes the aortic valve and so that the peaks of the supportstent are aligned with the tips of the natural leaflets of the aorticvalve 210. Therefore, when the THV is inserted and expanded within theaortic valve 210, the leaflets of the aortic valve will engage at leastthe majority of the surface in the interior of the support stent 10.This alignment will create an overall tighter fit between the supportstent 10 and the THV. In other embodiments, the support stent 10 isrotated and positioned as necessary so that the peaks of the supportstent 10 are aligned with the commissures or other portions of theaortic valve. The position of the guide catheter 102 and the supportstent 10 relative to the aortic valve 210, as well as the position ofother elements of the system, can be monitored using radiopaque markersand fluoroscopy, or using other imaging systems such as transesophagealecho, transthoracic echo, intravascular ultrasound imaging (“IVUS”), oran injectable dye that is radiopaque.

Also seen in FIG. 8 are the prongs of the outer fork 140 and the prongsof the inner fork 138. In the exemplary procedure, the prongs of theouter fork 140 and the inner fork 138 remain secured to the supportstent 10 until the THV is deployed and frictionally engaged to thesupport stent. The inner and outer forks desirably form a connectionbetween the stent 10 and the delivery system that is secure and rigidenough to allow the surgeon to hold the stent 10 at the desiredimplanted position against the flow of blood while the THV is beingimplanted.

In FIG. 8, the support stent 10 is self-expanding. In other embodiments,however, the support stent may not be self-expanding. In suchembodiments, the support stent can be made of a suitable ductilematerial, such as stainless steel. In addition, a mechanism forexpanding the support stent can be included as part of the deliverysystem 100. For example, the support stent can be disposed around aballoon of a balloon catheter in a compressed state. The ballooncatheter can have a shaft that is interior to the inner catheter 118.Because the stent 10 is not self-expanding, the distal end portion ofthe guide catheter 102 need not extend over the compressed supportstent. During delivery of the support stent, the support stent, ballooncatheter, inner catheter 118, and stent delivery catheter 108 can beadvanced from the distal end of the guide catheter 102. The balloonportion of the balloon catheter can be inflated, causing the supportstent to expand. The balloon portion can subsequently be deflated andthe balloon catheter withdrawn into the delivery system 100 to removethe balloon from the interior of the support stent while the supportstent remains connected to the inner catheter for positioning of thesupport stent. The delivery of the support stent otherwise proceeds asin the illustrated embodiment using the self-expanding support stent 10.

FIG. 9 shows an introducer sheath 220 passing into the left ventriclethrough a puncture 222 and over a guidewire 224 that extends upwardthrough the aortic valve 210. The surgeon locates a distal tip 221 ofthe introducer sheath 220 just to the inflow side of the aortic valve210. The position of the introducer sheath 220 relative to the aorticvalve 210, as well as the position of other elements of the system, canbe monitored using radiopaque markers and fluoroscopy, or using otherimaging systems.

FIG. 10 shows the advancement of the balloon catheter 230 over theguidewire 224 and through the introducer sheath 220. Ultimately, as seenin FIG. 11, the THV 250 is located at the aortic annulus and between thenative aortic leaflets. FIG. 11 also illustrates retraction of theintroducer sheath 220 from its more distal position in FIG. 10.Radiopaque markers may be provided on the distal end of the introducersheath 220 to more accurately determine its position relative to thevalve 210 and balloon 232. In order to better illustrate the componentsof the delivery system for the THV, FIGS. 10-11 do not show the frontthird of the support stent 10 or the corresponding outer and inner prongof the outer fork and the inner fork, respectively. Furthermore, forpurpose of illustrating the relative position of the support stent 10 onthe THV 250, FIGS. 12-13 show the front third of the support stent 10and the front of the THV 250, but do not show the portions of the nativeheart valve that would be secured by the front of the support stent 10.It is to be understood, however, that a corresponding leaflet of thenative heart valve would be secured between the support stent 10 and theTHV 250.

Again, the precise positioning of the THV 250 may be accomplished bylocating radiopaque markers on its distal and proximal ends. In someembodiments, the surgeon can adjust the position of the valve 250 byactuating a steering or deflecting mechanism within the balloon catheter230. Furthermore, the rotational orientation of the valve 250 can beadjusted relative to the cusps and commissures of the native aorticvalve by twisting the balloon catheter 230 from its proximal end andobserving specific markers on the valve (or balloon catheter) underfluoroscopy. One of the coronary ostia 280 opening into one of thesinuses of the ascending aorta is also shown in FIG. 11, and those ofskill in the art will understand that it is important not to occlude thetwo coronary ostia with the prosthetic valve 250.

FIG. 11 shows the THV 250 in its contracted or unexpanded state crimpedaround the balloon 232. When the surgeon is satisfied of the properpositioning and rotational orientation of the valve 250, the balloon 232is expanded to engage the support stent 10 as seen in FIG. 12. Theengagement of the support stent 10 to the exterior of the THV 250pinches the leaflets of the aortic valve between the support stent andthe THV 250, and thereby secures the THV within the annulus of theaortic valve. Once secured into this position, the inner catheter 118 ofthe delivery system 100 can be retracted, thereby causing the prongs ofthe inner fork 138 to become disengaged from the retaining arms of thesupport stent 10. Once the prongs of the inner fork 138 are disengaged,the prongs of the outer fork 140 can be disengaged from the retainingarms by retracting the stent delivery catheter 108. Once disengaged fromthe support stent, the delivery system 100 can be retracted from theaortic arch and removed from the patient.

It should be noted that the valve 250 can take a variety of differentforms and may comprise an expandable stent portion that supports a valvestructure, such as one or more leaflets sutured or otherwise secured tothe stent or frame of the valve 250. The stent portion desirably hassufficient radial strength to hold the valve at the treatment site andto securely engage the support stent 10. Additional details regardingballoon expandable valve embodiments that can be used in connection withthe disclosed technology are described in U.S. Pat. Nos. 6,730,118 and6,893,460, both of which are hereby expressly incorporated herein byreference.

Once the valve 250 is properly implanted, as seen in FIG. 13, theballoon 232 is deflated, and the entire delivery system including theballoon catheter 230 is withdrawn over the guidewire 224. The guidewire224 can then be withdrawn, followed by the introducer sheath 220.Ultimately, purse-string sutures 260 at the left ventricular apex can becinched tight and tied to close the puncture.

FIGS. 14 and 15 are perspective views of a support stent 300, accordingto another embodiment. The support stent 300 in the illustratedconfiguration comprises a plurality of struts arranged in a zig-zagpattern to form an annular body having a plurality of peaks and valleys:six peaks and six valleys in the illustrated embodiment. The stent caninclude a cover 302, which can be a cloth or fabric covering andextending around the struts of the support stent. The cover 302 can besutured or otherwise secured to the struts of the stent. The cover 302can be made from, for example, a fabric (e.g., polyethyleneterephthalate (PET)) (sold under the tradename Dacron®), ultra highmolecular weight polyethylene (UHMWPE) (sold under the tradename DyneemaPurity®), etc.), tissue (e.g., pericardial tissue), sponge, or anon-woven polymeric material such as silicone. FIGS. 16 and 17 show thesupport stent 300 without the cover 302 for purposes of illustration.The support stent 300 in the illustrated embodiment comprises a singleband, or hoop, comprised of a plurality of angled struts 304 arranged ina zig-zag pattern. The support stent 300 can further include one or moreretaining arms 306 (e.g., three equally spaced retaining arms 306 in theillustrated embodiment) extending from the apices of the struts 304 atone end of the band. The retaining arms 306 can be used to form areleasable connection with the distal end of a delivery apparatus, aspreviously described. Mounted to the inner surfaces of the struts 304are one or more projections, or protrusions, 308 (also referred to asnubs), that assist in retaining a THV 250 in the implanted positionwithin the interior of the support stent 300, as further describedbelow.

The protrusions 308 can take any of various forms. In the embodiment ofFIGS. 14 and 15, the protrusions 308 are formed by securing a knotted orwound ball 310 (FIG. 19) of suture material (or similar type ofelongated material) to the inner surfaces of the struts 304, which arethen covered by the fabric cover 302. As shown in FIGS. 16 and 17, everyother strut 304 is formed with a pair of openings 312 so that arespective suture ball 310 can be tied to each of those struts. Itshould be understood, however, that a pair of openings 312 can be formedin every strut 304, or in fewer than every strut 304, at one or moreselected locations. Also, a strut 304 can have more than one pair ofopenings 312 to allow more than one suture ball 310 to be secured tothat strut. The protrusion 308 can be formed by knotting, braiding,and/or winding any of various types of string, yarn, thread, chord,suture material, or other type of elongate material into the shape of,for example, a ball or sphere.

In particular embodiments, the protrusion comprises a suture ball 310,which can be formed by, for example, knitting, or braiding suturematerial into a length of multi-stranded suture knit or braid, as shownin FIG. 20. A triple wrap knot can then be formed in the suture knit,which for purposes of illustration is shown formed in a length of cordin FIG. 21. The suture knit can be cut on opposite sides of the knot andthen unraveled to form a knot 310 with two suture tails 314 extendingfrom the knot 310 (FIG. 19). As shown in FIG. 19, the suture tails 314can be threaded through respective openings 312 and tied to each otherso as to secure the suture ball 310 to the strut 304. FIG. 22 shows thesupport stent 300 after several suture balls 310 have been tied to thestruts 304 of the stent. After the desired number of suture balls 310have been secured to the stent 300, the struts 304 and the suture balls310 can be covered with the cover 302 using known techniques.

Moreover, it should be understood that other techniques or mechanismscan be used to secure the suture balls 310 to the struts. For example,one or more selected struts 304 can have a single opening 312 for tyinga respective suture ball 310 to each of those struts. In anotherimplementation, the sutures 314 can be tied around the outside orperimeter of a strut 304. In another implementation, the suture balls310 can be secured to the struts using an adhesive.

Preferably, although not necessarily, the projections 308 are positionedalong the inner surfaces of the struts 304 so that they can extendthrough openings in the cells of the frame of a THV 250 when the supportstent is implanted. FIG. 23 shows the support stent 300 placed around astent, or frame, 350 of a THV. For purposes of illustration, theprosthetic leaflets of the THV (which are secured to the inside of theframe 350) and the leaflets of the native valve are not shown in FIG.23. Typically, the leaflets of the native valve are interposed betweenthe frame 350 and the support stent 300 after implantation, aspreviously described. As shown, the frame 350 comprises a plurality ofstruts 352 arranged to form a plurality of openings 354 at the outflowend of the frame and a plurality of larger openings 356 at the inflowend of the frame. The projections 308 desirably are positioned such thatwhen the support stent 300 is positioned around the frame 350, theprojections 308 extend through respective openings 354, 356 in theframe. FIG. 24 shows the support stent 300 implanted on the outside of aTHV 250 with the native leaflets 210 of the aortic valve interposed andpinched between the support stent 300 and the THV. The forward half ofthe support stent 300 is removed in this view for purposes ofillustration. As depicted in FIG. 24, the projections 308 extendradially inwardly into the openings of the THV's frame, thereby pressingportions of the native leaflets 210 into the openings of the THV's frame(e.g., openings 354, 356 in FIG. 23). The action of the projections 308pressing the native leaflets 210 inwardly into the openings of the frameincreases the retention force of the support stent against the THV 250,and therefore better resists dislodgement of the THV. In this manner,the projections 308 function as an interlocking feature to assist inretaining the THV in the implanted position.

FIG. 25 is a flattened view of the frame 350 superimposed on top of thesupport stent 300. FIG. 25 shows the desired position of the supportstent 300 relative to the frame 350 when both components are implanted,although both components are shown in a flattened or unrolledconfiguration for purposes of illustration. The suture balls 310 can bepositioned at any locations on the struts 304 that would allow thesuture balls 310 to project inwardly into the openings 354, 356 of theframe 350. FIG. 26 is a flattened view of a frame 360, according toanother embodiment, superimposed on top of the support stent 300. Theframe 360 in this embodiment has a first row of openings 362 at theoutflow end of the frame, a second, intermediate row of openings 364,and a third row of openings 366 at the inflow end of the frame. Thesuture balls 310 can be positioned at any locations on the struts 304that would allow the suture balls 310 to projection inwardly into one ormore of openings 362, 364, 366 of the frame 360.

In particular embodiments, the diameter of the suture ball 310 is fromabout 1.4 mm to about 1.9 mm, although the size of an individual sutureball can vary depending on the application and various factors, such asthe size of the openings in the THV's frame and the total number ofsuture balls secured to the stent.

FIG. 27 is a perspective view of a support stent 300′, according toanother embodiment. The support stent 300′ is similar to support stent300, except that the support stent 300′ includes additional struts 320arranged in pairs between pairs of struts 304. Each strut 320 has oneend connected to a strut 304 (e.g., at about the mid-point of the strut304) and another end connected to the end of an adjacent strut 320 toform an apex 321. The retaining arms 306 can extend from respectiveapices 321. Each pair of struts 320 forms a closed, diamond-shape cellwith portions of a respective pair of struts 304. The diamond-shapecells increase the radial strength of the support stent 300′, andtherefore can increase the retention force against a THV mounted withinthe support stent 300′. Although not shown, the apices 321 and/or theapices 322 between struts 304 can be bent or can be curved inwardlytoward the central flow axis of the support stent to increase theretention force against a THV implanted within the support stent 300′.The support stent 300′ optionally can include projections 308 (such assuture balls) and a cover 302, similar to the support stent 300.

FIG. 28 is a cross-sectional view of a support stent 400, according toanother embodiment. The support stent 400 can comprise multiple strutsthat can be arranged in a configuration similar to FIGS. 16-17. Multipleretaining arms 402 can extend from one end of the support stent 400. Thesupport stent 400 includes multiple projections 404 circumferentiallyspaced around one end of the stent. The projections 404 in theillustrated embodiment extend radially inwardly and are perpendicular tothe longitudinal flow axis of the support stent. Each projection 404 canbe an extension of a strut 406 and can be bent inwardly relative to thestrut 406 during the manufacturing process. FIG. 29 shows a top planview of a single projection 404. The support stent can further include acover 408 (e.g., a fabric cover) covering the struts 406 and theprojections 404. As shown in FIG. 28, the THV 250 can be implanted suchthat its outflow end 252 is adjacent the lower surfaces of theprojections 404. In this manner, the projections 404 can resistdislodgement of the THV 250 in the direction of the flow of blood towardthe aorta, and/or position the THV 250 during deployment thereof. Inanother implementation, the THV can be implanted relative to the supportstent 400 such that the projections 404 can extend into the openings ofthe frame of the THV.

FIGS. 30-48 show various ways that a projection can be formed on ormounted to a strut of a support stent, such as support stent 300.Although not shown, any of the embodiments described below can include acover (e.g., cover 302) that covers the stent and the projections formedon or mounted to the stent. FIGS. 30 and 31 show perspective assembledand exploded views of a separately formed projection member 602configured to be mounted on a strut 600 of a support stent. Theprojection member 602 includes a base 604 and a projection 606 extendingfrom the base. The base 604 can be configured to form a snap-fitconnection with the strut 600, or alternatively, can be welded oradhesively secured to the strut 600. The base 604 and the projection 606can be made from any of various suitable materials, such as metals(e.g., stainless steel) or any of various elastomeric or non-elastomericpolymers (e.g., polyurethane, nylon, silicone).

FIGS. 32-33 show a strut 610 of a support stent. The strut 610 has amain strut body 612 and first and second laterally extending arms 614,616. The arms 614, 616 can be bent or folded along fold lines 618 sothat arm 616 is folded on top of arm 614 to effectively form aprojection extending from the strut 610.

FIG. 34 shows a strut 620 formed with an opening 622. A projection 624can be secured to the strut 620 by inserting a pin 626 of the projection624 into the opening 622. The projection 624 can be welded to the strut620, secured to the strut 620 with a suitable adhesive, peened, swagedor deformed to create an interference fit with the opening 622, and/orthe projection 624 can be sized to form a friction fit with the opening622. The projection 624 can be made from any of various suitablematerials, such as metals (e.g., stainless steel) or any of variouselastomeric or non-elastomeric polymers (e.g., polyurethane, nylon,silicone).

FIG. 35 shows a projection 630 in the form of a small sphere or beadhaving an opening 632 extending therethrough. The projection 630 can besecured to a strut 634 using a suture 636 extending through the opening632 in the projection and an opening 638 in the strut 634. The suture636 can be tied off or knotted at its opposite ends to secure theprojection 630 in place. FIG. 36 shows a projection 630 tied to a strut640 by a suture 642 that extends through the opening 632 in theprojection and wraps around the strut 640. The strut 640 can include arecessed or narrowed portion 644 around which the suture 642 is wrappedto prevent the projection from sliding along the length of the strut.The projection 630 can be made from any of various suitable materials,such as metals (e.g., stainless steel) or any of various elastomeric ornon-elastomeric polymers (e.g., polyurethane, nylon, silicone).

FIG. 37 shows a projection 650 formed from multiple layers 652 ofmaterial, such as layers of fabric (such as used to form the cover 302of the stent), stacked on top of each other. The material layers 652 canbe tied to a strut 654 by a suture 656 extending through the materiallayers 652 and corresponding openings in the strut 654. In someembodiments, the projection 650 comprises a single layer 652 ofmaterial, for example, metal, polymer, fabric, sponge, or silicone, tiedto the strut 652.

FIG. 38 shows a strut 660 formed with a shape set projection 662. Inthis embodiment, the strut 660 and the projection 662 can be formed froma suitable self-expanding or shape-set material, such as nitinol. Theprojection 662 can be folded against the strut 660 during delivery ofthe support stent. When the support stent is radially expanded (such asafter being deployed from a delivery sheath), the projection 662 canpivot outwardly relative to the strut 660 to the position shown in FIG.38.

FIG. 39 shows a projection in the form of a rivet 670 comprising a headportion 672 and a pin 674. The pin 674 can be inserted into an opening682 of a strut 680 and secured in place by bending or deforming the endportions 676 of the pin 674, as depicted in FIG. 40. The rivet 670 canbe made of any of various biocompatible metals, such as stainless steel,or other malleable materials.

FIGS. 41 and 42 show a projection 690 formed by molding a polymer on astrut 692. The molded projection 690 can have a inwardly facingprojection portion 694 (which contacts the native leaflets whenimplanted), an intermediate portion 696 formed in an opening extendingthrough the strut 692, and an outwardly facing projection portion 698that has a diameter greater than that of the opening in the strut toretain the projection in place against the strut. The projection 690 canbe made from any of various elastomeric or non-elastomeric polymers(e.g., polyurethane, nylon, silicone).

FIG. 43 shows a projection 700 in the form of a ball of cloth that canbe tied to a strut 702 with a suture 704.

FIG. 44 shows a projection 710 in the form of a cylindrical body 710.The projection 710 can be tied to a strut 712 by a suture 714 thatextends through the body 710 and openings in the strut. The projection710 can be made from any of various suitable materials, such as metals(e.g., stainless steel) or any of various elastomeric or non-elastomericpolymers (e.g., polyurethane, nylon, silicone).

FIGS. 45 and 46 show a projection 716 configured to be mounted on astrut 718 of a support stent. The projection 716 can be shaped so as toform a three-sided channel 720 through which a portion of the strut 718extends. The projection 716 can be formed from an elastomeric material,such as silicone, to provide the support stent with a greater grippingforce against the native leaflets and a THV deployed within the nativeleaflets. The projection 716 can be formed with bristles 720 that cancontact the native leaflets when implanted. The bristles 720 can furtherenhance the gripping force of the support stent against the nativeleaflets. The projection 716 can be secured to the strut 718, such aswith an adhesive or molding the projection to the strut. In otherembodiments, the projection 716 can be made of metal and can be weldedto the strut.

FIG. 47 shows a projection 730 in the form of a rivet that can besecured within an opening 732 of a strut 734. The projection 730 caninclude an enlarged head portion 736 (which contacts the native leafletswhen implanted), a shaft 738 and a retaining member 740. The projection730, or at least the retaining member 740, can be made of an elastomericand/or resilient material (e.g., polyurethane, nylon, silicone), so thatthe retaining member can be radially compressed and pressed through theopening 732 in the strut and then can expand back its normal size andshape when it passes through the opening. When installed on the strut,the retaining member 740 is on the opposite side of the strut from thehead portion 736 and therefore retains the projection in place. The headportion 736 can be any of various shapes, such as a sphere or a portionof a sphere. FIG. 48 shows a similar projection 730′ having a headportion 736′ shaped as a cube.

FIG. 49 shows the distal end portion of a delivery apparatus 800 forimplanting a support stent, such as support stent 10 or 300. Thedelivery apparatus 800 comprises an outer shaft or sheath 802 from whicha plurality of attachment arms 804 extend. Each attachment arm 804 ispaired with a respective release wire 806, which together form areleasable connection with a respective retaining arm of a support stent(e.g., retaining arms 306 of the support stent 300). The illustratedembodiment includes three pairs of attachment arms 804 and release wires806 to correspond with the three retaining arms 306 of the support stent300. The attachment arms 804 can be connected to an inner shaft, orpusher member, 803 that extends coaxially through the outer shaft 802.The release wires 806 can extend alongside or through the inner shaft803 the length of the delivery apparatus to a handle (not shown) formanipulation by a user. Alternatively, the release wires 806 can beconnected to another shaft or a common pull wire that extends through oralongside the inner shaft 803 such that all three release wires can bemove together by moving the additional shaft or pull wire.

A respective sheath 808 extends over each pair of an attachment arm 804and a release wire 806. The sheaths 808 prevent the release wire 806from kinking when the support stent is being deployed inside the bodyand when the pull wire is retracted to release the support stent, asfurther described below. During delivery of a support stent 300, thesupport stent, the attachment arms 804 and the release wires 806 arecontained within the sheath 802. When the support stent is at oradjacent the implantation site, the support stent, the attachment arms,and the release wires can be advanced from the distal opening of thesheath 802, as depicted in FIG. 49.

The attachment arms 804 and release wires 806 can be connected to theretaining arms 306 of the support stent much like the inner and outerforks 138, 140, respectively, described above. Referring to FIGS. 50 and51, the upper end portion of a retaining arm 306 is inserted through anopening 810 of an attachment arm 804. The distal end portion of arelease wire 806 is then inserted through an opening 307 in theretaining arm 306. The release wire 806 prevents the retaining arm 306from disconnecting from the attachment arm 804 until the release wire isretracted from the opening 307. As shown in FIGS. 50-51, the attachmentarm 804 and the release wire 806 are relatively flexible and bowoutwardly when advanced from the sheath 802 during deployment of thesupport stent 300. Hence, as shown in FIGS. 52 and 53, the sheath 808extends over the attachment arm 804 and the release wire 806 and keepsthem in close proximity to prevent the release wire 806 and theattachment arm 804 from kinking and/or bowing outwardly relative to eachother when advanced from the main sheath 802 and when the pull wire isretracted to release the support stent.

In particular embodiments, two separate delivery systems can be used toat least partially simultaneously deliver a support stent and aprosthetic heart valve to the outflow side of the aortic arch. Forillustrative purposes, such dual system approaches are described withrespect to approaches that at least partially simultaneously approachthe outflow side of the aortic valve (e.g., through the ascendingaorta), although similar techniques can be used to deploy the supportstent and the prosthetic heart valve from the inflow side of the aorticvalve.

When delivering the support stent and the prosthetic heart valvetransfemorally using two separate delivery systems, access to the aorticvalve can be obtained through different access routes or points. Forexample, the support stent delivery system can be delivered through theleft femoral artery while the prosthetic heart valve delivery system canbe delivered through the right femoral artery, or vice versa. In otherembodiments, the support stent delivery system can be delivered throughthe carotid artery (e.g., through the right carotid artery and into thebrachiocephalic artery or through the left carotid artery) or throughthe subclavian artery (e.g., through the right subclavian artery andinto the brachiocephalic artery or through the left subclavian artery)and toward the outflow side of the aortic valve while the prostheticheart valve delivery system can be delivered transfemorally (e.g.,through the left or right femoral artery), or vice versa. Using thecarotid or subclavian arteries can provide a more direct approach to theaortic valve than through a femoral artery and over the aortic arch,thus making such an approach potentially more desirable for deliveringthe support stent or prosthetic heart valve.

FIG. 54 illustrates one exemplary system and procedure for deploying thesupport stent and securing a prosthetic valve to the support stent usinga multi-system approach where the multiple delivery systems are atpartially simultaneously advanced toward the outflow side of the aorticvalve. In particular, FIG. 54 is a cross-sectional view through the leftside of a patient's heart showing acts performed in delivering a supportstent 300 from the outflow side of the aortic valve.

FIG. 54 shows a main catheter 802 of a support stent delivery system 800as it is advanced into a position near the surface of the outflow sideof the aortic valve 820. The support stent delivery system 800 can beinserted through one of the femoral arteries of the patient or throughone of the carotid or subclavian arteries, and advanced into the aortain the retrograde direction. FIG. 54 also shows a main catheter 832 of aprosthetic heart valve delivery system 830. The prosthetic valvedelivery system 830 can be inserted through another one of the femoralarteries of the patient or through the carotid or subclavian arteries(if the support stent delivery system 800 is advanced transfemorally)and also advanced into the aorta in the retrograde direction. FIG. 54additionally shows attachment arms 804, release wires 806, and thesheaths 808 extending from the distal opening of the main shaft 802 andcoupled to respective retaining arms of the support stent 300. FIG. 54further shows a prosthetic valve delivery catheter 834 (a ballooncatheter in the illustrated embodiment), nose cone 836, and guidewire838, which is shown as being extended through the aortic valve 820. Inthe illustrated embodiment, the prosthetic valve delivery catheter 834is advanced to the point where a balloon portion 840 around which theprosthetic valve 842 is compressed and nose cone 836 are locatedadjacent to an inflow side of the native leaflets of the aortic valve.Furthermore, in FIG. 54, the inner shaft 803 is advanced from the outershaft 802, allowing the support stent 300 to expand into itsuncompressed, natural shape in a position above the aortic valve 820.

In order for the prosthetic valve delivery catheter 834 to be advancedthrough the aortic valve as shown, the attachment arms 804, the releasewires 806, and the sheaths 808 are desirably configured so that theyarch radially outward from the end of the inner shaft 803. The sheaths808 keep the release wires in close alignment with their respectiveattachment arms and keep the release wires from kinking when they aremoved to release the support stent. Together, the attachment arms 804,the release wires 806, and the sheaths 808 can be said to form aglobe-like or pumpkin-like shape. This shape increases the space betweenthe pairs of attachment arms and release wires, and creates a sufficientopening through which the nose cone 836, balloon portion 840, prostheticvalve 842, and prosthetic valve delivery catheter 834 can be advancedinto the illustrated position.

Deployment of the prosthetic valve 842 can be achieved by positioningthe prosthetic valve between the native leaflets of the aortic valve andinflating the balloon 840, causing the prosthetic valve to radiallyexpand until the native leaflets are pinched between the support stent300 and the prosthetic valve. The prosthetic valve delivery system 830can then be retracted to remove the balloon catheter 834 from the spacebetween the attachment arms. The support stent 300 can then be releasedfrom the support stent delivery system 800 by retracting the releasewires 806.

It should be understood that the exemplary systems shown in FIG. 54 areby way of example and that any suitable support stent delivery systemdisclosed herein or suitable prosthetic heart valve delivery systemdisclosed herein can be used as part of a dual system delivery method.

As illustrated by the various delivery systems and approaches describedin this disclosure, there are many delivery options available to boththe patient and the physician for delivering a prosthetic heart valvesecured by a support stent. In order to determine which of the systemsand approaches is most suitable for a particular patient, the patientcan be screened. For example, the patient can be screened forvasculature tortuosity and/or apical integrity. Depending on the patientetiology, a transfemoral approach may be a more appropriate mode ofdelivering the devices, or vice versa.

FIG. 55A shows the distal end portion of a delivery apparatus comprisinga steerable outer shaft 900, the distal end portion of which comprises asheath 902 for containing an expandable implant, such as the illustratedsupport stent 300. The support stent 300 can be releasably connected tothe distal end of an inner shaft (not shown) via an attachment assemblyor mechanism, such as the attachment arms 804 and release wires 806, asdescribed above. The inner shaft (also referred to as a “pusher member”)extends coaxially through the outer shaft and has a proximal end portioncoupled to a handle mechanism (not shown). The outer shaft 900 containsone or more pull wires to control the curvature of the deliveryapparatus as it is advanced through the aortic arch, as is well known inthe art.

As discussed above, the support stent 300 can have one or moreprojections 308 (FIG. 14). The portion of the support stent without anyprojections 308 may be radially compressible to a smaller diameter thanthe portion of the support stent having the projections 308.Consequently, as shown in FIG. 55A, the support stent 300 can be crimpedand loaded into the sheath for delivery into a patient's vasculaturesuch that the portion of the support stent having the projections 308extends outwardly from the sheath. In this manner, the sheath can besized for the smallest possible crimped diameter of the support stent(which corresponds to the portion of the support stent 300 without anyprojections 308) to minimize the overall profile of the deliveryapparatus.

In use, when the deflection of the outer shaft is increased, it issubject to compressive forces due to the pull wires, causing the outershaft to decrease in length. As illustrated in FIGS. 55B-55E, thisshortening of the shaft 900 can cause the support stent 300 toprematurely advance from the sheath 902.

To prevent such premature deployment of the support stent, the innershaft can be configured to slide axially relative to the outer shaft 900as the outer shaft is deflected by the pull wires. In accordance withone embodiment, FIG. 56 shows the internal mechanism of a handle of thedelivery apparatus that allows such sliding movement of the inner shaft.As shown, the handle contains a drive mechanism 904 operativelyconnected to the proximal end portion of an inner shaft 906. The drivemechanism 904 comprises a distal portion 908 spaced from a proximal endportion 910 and a gap 912 between the distal portion and the proximalend portion. The inner shaft 906 extends through and is slidablerelative to the distal portion 908 and the proximal portion 910 in thedistal and proximal directions. In the space between the distal portion908 and the proximal portion 910, the shaft 906 has a plurality ofaxially spaced annular grooves 914. An adjustable stop member, such asin the form of a ring or clip 916, is mounted on the shaft 906 within aselected groove 914 and allows a limited amount of axial movement of theshaft 906 relative the driving mechanism 904 equal to the length of thegap 912. The clip 916 can be a C-shaped clip (i.e., an annular ringhaving a gap) that can be press fitted onto the shaft 906 within one ofthe grooves 914.

FIG. 57 shows an exemplary handle 1000 for the delivery apparatus. Theproximal end of the outer shaft 900 can be secured to the handle. Theproximal end portion of the inner shaft 906 can extend into the handlewhere it is supported by the drive mechanism 904. The handle 1000 canhave an adjustment mechanism 1022 in the form of a rotatable knob thatis configured to adjust the curvature of the outer shaft 900. Thedelivery apparatus can have one or more pull wires that extendlongitudinally through the outer shaft and have proximal end portionsoperatively connected to the adjustment mechanism 1022. Rotation of theknob 1022 is effective to adjust the curvature of the outer shaft byadjusting the tension of the one or more pull wires. Further details ofthe adjustment mechanism are disclosed in U.S. Patent ApplicationPublication No. 2009/0281619 A1, which is incorporated herein byreference. The distal end of the inner shaft 906 can be releasablyconnected to a support stent 300, such as through the attachment arms804 and the release wires 806 (FIG. 49). During delivery through apatient's vasculature, the support stent 300, the attachment arms 804,and the sheaths 808 can be housed in the distal end portion of the outershaft 900.

In use, as the outer shaft 900 is deflected and slightly foreshortenedby the compressive forces on the shaft, the inner shaft 906 (and thusthe support stent 300) can slide proximally relative to the outer shaft(in the direction of arrow 920, FIG. 56) to prevent premature exposureof the support stent from the distal sheath 902. Proximal movement ofthe shaft 906 is limited by contact of the clip 916 against the proximalportion 910 of the drive mechanism. Distal movement of the shaft 906relative to the outer shaft 900 is limited by contact of the clipagainst the distal portion 908 of the drive mechanism. When the distalend of the delivery apparatus is at or near the desired deploymentlocation for the support stent within the body (e.g., within the aorticroot), the support stent can be deployed from the sheath 902 by movingthe drive mechanism distally. As the drive mechanism 904 is advanced,the proximal portion 910 bears against the clip 916, which causes theinner shaft (and thus the support stent 300) to move distally relativeto the outer shaft to deploy the support stent from the sheath 902.Conversely, the outer shaft 900 can be retracted proximally relative tothe inner shaft 906 and the drive mechanism to deploy the support stent.As the outer shaft 900 is retracted, the clip 916 bears against thedistal portion 908 of the drive mechanism to retain the inner shaft 906in a stationary position relative to the drive mechanism.

Also, due to manufacturing constraints, the overall lengths of the outershaft 900 and the inner shaft 906 can vary slightly amongst individualdelivery apparatuses. For example, the steerable outer shaft of thedelivery apparatus can be purchased from various manufacturers. Theoverall length of the outer shaft can vary amongst differentmanufacturers or amongst the same manufacturer. When assembling thedelivery apparatus, the inner shaft 906 needs to be axially alignedwithin the outer shaft such that the support stent 300 can be retainedwithin the distal sheath 902 during the implantation procedure untilsuch time the physician actuates a mechanism on the handle to deploy thestent. During the assembly process, the inner shaft 906 is insertedthrough the drive mechanism 904 and the axial positioning of the shaft906 is adjusted until the desired position of the shaft 906 relative theouter shaft is achieved. The clip 916 is then placed on the shaft 906within a selected groove 914 to retain the proximal end portion of theinner shaft within the handle. As can be appreciated, the multiplegrooves 914 on the inner shaft allow the axial positioning of the innershaft to be adjusted to compensate for any variations in the overalllength of the inner shaft and/or the outer shaft.

The handle 1000 in the illustrated embodiment can further include arotatable knob 1002 that is configured to control the deployment of animplant (e.g., support stent 300) from the sheath of the deliveryapparatus (e.g., the distal end portion of the outer shaft 900). Forexample, the rotatable knob 1002 can be operatively connected to thedrive mechanism 904 (FIG. 56) to control distal and proximal movement ofthe drive mechanism (and thus the inner shaft 906 and the support stent)relative to the outer shaft. For this purpose, the knob 1002 can includean internal pinion gear 1004 (FIG. 58) that engages teeth of a rack onthe drive mechanism 904. In this manner, rotation of the knob 1002causes corresponding axial movement of the drive mechanism and the innershaft.

As the knob 1002 is rotated to expose the implant, the outer shaft 900is stretched elastically and the inner shaft 906 is compressedelastically. The forces on the inner and outer shafts impart a force onthe knob 1002 that urges the knob in a direction opposite the rotationalforce applied to the knob by the user. Removal of manual pressure fromthe knob can cause “spring-back” of the sheath, pulling the implant backinto the sheath. Referring to FIG. 58, to better control deployment ofthe implant, a biasing member, such as the illustrated spring 1006, canbe employed to increase the friction on the knob 1002. The spring 1006is mounted on a pin 1008 within the handle 1000. The spring 1006comprises a first spring portion 1010 that bears against an adjacentsurface 1012 inside the handle, a second spring portion 1014 positionedto engage nubs, or ribs, 1016, spaced around the outer surface of theknob 1002, and a third, S-shaped intermediate portion 1018 that bearsagainst an adjacent surface 1020 inside the handle. The second springportion 1014 is long enough to contact each of the ribs 1016 as the knobis rotated but not the outer surface of the knob between adjacent ribs.Due to the curvature of the intermediate portion 1018, the second springportion 1014 has a greater resistance when it is deflected downwardlycompared to when it is deflected upwardly. In use, when the knob isrotated in a first direction to advance the inner shaft 906 to deploythe support stent (clockwise in FIG. 58), the second spring portion 1014is deflected slightly upwardly each time one of the ribs 1016 on theknob comes into contact with the spring portion 1014. The action of theribs 1016 pushing upwardly on the spring portion 1014 as the knob isrotated provides the user with tactile feedback regarding the degree ofrotation of the knob, which corresponds to the degree of advancement ofthe implant from the sheath. The contact between the ribs 1016 and thespring portion 1014 also generates an audible “clicking” sound, therebyproviding audible feedback to the user. If manual pressure on the knobis reduced or released during the deployment phase, the forces impartedon the knob due to elastic deformation of the outer and inner shafts900, 906 is resisted by the spring force of the spring portion 1014acting on the knob in the opposite direction. In other words, if theelastic deformation of the shafts urges the knob in the counterclockwisedirection in FIG. 58, the biasing force of the spring portion 1014 cancounteract that movement and prevent rotation of the knob in thecounterclockwise direction, which would otherwise cause the implant tobe drawn back into the sheath 902. As noted above, the spring portion1014 has a greater resistance when it is deflected downwardly comparedto when it is deflected upwardly. Thus, the spring portion 1014 providesa greater resistance against rotation of the knob for counterclockwiserotation as compared to its resistance against rotation for clockwiserotation. The spring therefore can be said to provide asymmetricfriction control of the knob, which allows relatively easy rotation ofthe knob for deployment of the implant (in the clockwise direction inthe illustrated embodiment) and increases the resistance on the knob inthe opposite direction to prevent “spring back” of the inner shaftrelative to the outer shaft.

In alternative embodiments, other types of biasing members can be usedto apply resistance against rotation of the knob, such as torsionsprings, elastomeric members, etc.

In view of the many possible embodiments to which the principles of thedisclosed invention may be applied, it should be recognized that theillustrated embodiments are only preferred examples of the invention andshould not be taken as limiting the scope of the invention. Rather, thescope of the invention is defined by the following claims. We thereforeclaim as our invention all that comes within the scope and spirit ofthese claims.

We claim:
 1. A method of treating aortic insufficiency, comprising:delivering a support structure to a position on or adjacent to a surfaceof the outflow side of a native heart valve of a patient, the supportstructure comprising an annular metal frame defining an interior and atleast one projection comprising a non-metallic material and extendingradially inwardly from the metal frame; positioning the supportstructure around the leaflets of the native heart valve such that theleaflets of the native heart valve are located within the interior ofthe metal frame; advancing an expandable prosthetic heart valve into thenative heart valve and into the interior of the metal frame, theprosthetic heart valve comprising a radially expandable annular framedefining a plurality of openings; and expanding the expandableprosthetic heart valve into contact with the leaflets of the nativevalve, thereby causing the leaflets of the native valve to befrictionally secured between an inner surface of the metal frame and anouter surface of the prosthetic heart valve and causing the at least oneprojection and a portion of one of the leaflets contacted by the atleast one projection to extend into one of said openings of the frame ofthe prosthetic heart valve; wherein the metal frame comprises aplurality of struts and a pair of apertures formed in at least one ofthe struts, and the at least one projection comprises a wound or knottedball of suture material disposed radially inwardly relative to the atleast one of the struts, and two suture tails extending from oppositesides of the wound or knotted ball, wherein the suture tails arethreaded radially outwardly through the pair of apertures and tied toeach other at a location radially outwardly relative to the at least oneof the struts to secure the at least one projection to the at least oneof the struts.
 2. The method of claim 1, wherein the metal framecomprises an inflow end and an outflow end, and the at least oneprojection is located along the length of the metal frame between theinflow and outflow ends.
 3. The method of claim 1, wherein the at leastone projection comprises a plurality of projections extending radiallyinwardly from the metal frame, and when the prosthetic heart valve isexpanded to contact the leaflets of the native valve, each projectionand a portion of one of the leaflets contacted by the projection arecaused to extend into one of said openings of the frame.
 4. The methodof claim 1, wherein the act of advancing the prosthetic valve into thenative heart valve is performed after the support structure ispositioned around the leaflets of the native heart valve and while thesupport structure is maintained in a substantially fixed positionrelative to the native heart valve.
 5. An assembly for treating aorticinsufficiency, comprising: a prosthetic heart valve configured to beimplanted within a native heart valve, the prosthetic heart valvecomprising a radially expandable annular frame defining a plurality ofopenings; and a support stent configured to be implanted around nativeleaflets of the native heart valve such that the native leaflets can befrictionally secured between the support stent and the prosthetic heartvalve, the support stent comprising an annular metal frame that definesone or more peaks and one or more valleys along its circumference, thesupport stent frame being radially compressible into a compressed stateand self-expandable into an uncompressed state, the support stentfurther comprising at least one projection comprising a non-metallicmaterial, the at least one projection extending radially inwardly fromthe support stent frame and configured to press a portion of one of thenative leaflets into one of the openings of the frame of the prostheticheart valve, wherein the metal frame comprises a plurality of struts anda pair of apertures formed in at least one of the struts, wherein the atleast one projection comprises a knotted or wound ball of suturematerial disposed radially inwardly relative to the at least one of thestruts, and two suture tails extending from opposite sides of theknotted or wound ball, wherein the suture tails are threaded radiallyoutwardly through the pair of apertures and tied to each other at alocation radially outwardly relative to the at least one of the strutsto secure the at least one projection to the at least one of the struts.6. The assembly of claim 5, wherein the support stent is sized such thatit can be positioned within the aorta of a patient at a locationadjacent to the aortic valve and thereby circumscribe the nativeleaflets of the aortic valve.
 7. The assembly of claim 5, wherein thesupport stent further comprises a fabric cover covering the supportstent frame and the at least one projection.
 8. The assembly of claim 5,wherein the support stent includes an inflow end and an outflow end, andthe at least one projection is located along a length of the supportstent between the inflow and outflow ends.
 9. The assembly of claim 5,wherein the at least one projection comprises a plurality of projectionsextending radially inwardly from the annular metal frame of the supportstent, and wherein the plurality of projections are configured suchthat, when the prosthetic heart valve is expanded to contact the nativeleaflets of the native heart valve, each of the plurality of projectionsand a portion of one of the native leaflets are caused to extend intoone of the plurality of openings of the annular frame of the prostheticheart valve, wherein each projection is secured to one of the struts ofthe metal frame with two respective suture tails extending outwardlythrough a pair of apertures in the corresponding strut.
 10. The assemblyof claim 5, wherein the knotted or wound ball comprises a triple wrapknot formed by a multi-stranded suture knit or braid.
 11. The assemblyof claim 5, wherein the at least one of the struts comprises a pluralityof pairs of apertures and the at least one projection comprises aplurality of knotted or wound balls, each of which is secured to arespective pair of apertures.
 12. The assembly of claim 5, wherein theat least one projection comprises a knotted ball of suture material. 13.An assembly for treating aortic insufficiency, comprising: a prostheticheart valve configured to be implanted within a native heart valve, theprosthetic heart valve comprising a radially expandable annular framedefining a plurality of openings; and a support stent configured to beimplanted around native leaflets of the native heart valve such that thenative leaflets can be frictionally secured between the support stentand the prosthetic heart valve, the support stent comprising an annularmetal frame comprising a plurality of struts arranged to define one ormore peaks and one or more valleys along a circumference of the frame,the support stent frame being radially compressible into a compressedstate and self-expandable into an uncompressed state; wherein thesupport stent further comprises a plurality of projections comprising anon-metallic material, the plurality of projections extending radiallyinwardly from the struts of the metal frame, wherein the plurality ofprojections are configured such that, when the prosthetic heart valve isexpanded to contact the native leaflets of the native heart valve, eachof the plurality of projections and a portion of one of the nativeleaflets are caused to extend into one of the plurality of openings ofthe annular frame of the prosthetic heart; wherein each projectioncomprises a knotted or wound ball of suture material disposed radiallyinwardly relative to an adjacent strut of the metal frame, and twosuture tails extending from opposite sides of the knotted or wound balland threaded radially outwardly through respective apertures in theadjacent strut, with the suture tails being tied to each other at alocation radially outwardly relative to the adjacent strut to secure theknotted or wound ball of suture material to the adjacent strut; whereinthe projections are secured to respective struts at locations betweenopposing ends of the struts; wherein the support stent further comprisesa fabric cover covering the struts and the projections.
 14. The assemblyof claim 13, wherein each projection comprises a knotted ball of suturematerial.